SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
The device implements 16 sampled-on-reset sysboot pads.
| Pads(1) | Description |
|---|---|
| sysboot[15] | Must be pulled to vdd for proper device operation (SR1.0). (2)Used to permanently disable the internal PU/PD resistors on pads gpmc_a[27:24, 22:19] (SR2.x). |
| sysboot[14] | Must be pulled to vss for proper device operation. |
| sysboot[13:10] | Used to configure the GPMC interface when booting from XIP memory connected to GPMC. See Table 33-6. |
| sysboot[9:8] | Selects the SYS_CLK1 clock speed. They must be set correctly according to the speed of the connected crystal. See Table 33-7. |
| sysboot[7:6] | Sector offset for the location of the redundant SBL images in QSPI. |
| sysboot[5:0] | Select interfaces or devices for the booting list. See Table 33-9. |
| sysboot[15](1) | mmc2_dat[7:0] Pull-down Resistors |
|---|---|
| 0b0 | Internal pull-down resistors permanently disabled to avoid contention with the recommended per eMMC standard pull-ups that should be present on PCB. Software re-configuration of internal pull resistors is disabled. |
| 0b1 | Software re-configuration of pull resistors is allowed. Internal pull-downs on gpmc_a[n:19] are enabled by default to allow GPMC boot. Pulling low gpmc_a[n:19] is required in order to access the low-order address locations in the flash memory during boot (n = [27:24, 22:19] and depends on the memory volume). |
All sysboot pads are sampled and latched onto the CTRL_CORE_BOOTSTRAP register (in control module) after POR. After booting, these pads can be used for other functions such as GPIOs, and the associated register bit field is not updated by the new functionality. For more information about pad multiplexing configuration, see Pad Configuration Registers, in Control Module.
If used as GPIOs, the sysboot[15:0] pads must be used only in output mode to ensure that the input values always match a certain hardware predefined boot pattern, interpreted after each POR.